In my exploring of options for bike sound system builds, I am yet to be compelled by anything more complex than a bass reflex - the ability to adapt aspect ratio to suit its mode of transport (ie on a cargo bike or trailer) is really handy, and the gains from TH aren't realised in a small box with a humble amount of battery powered amplification
And as you mentioned, crossing higher means you can run smaller tops too!
For a first build, maybe reset the plans and go for a simple vented box
The next step up to consider would be bandpass, slightly more complex to design but easy enough to build
And leave the tapped horns for when you get serious - ie on a Carla Cargo trailer with electric assist
Before you throw the towel on TH's and go for BR, check this 12" TH.
Called the PAL12
It was designed for he LAB12 driver
But sim well with other 12's
I can recommend you some 12's that I have simmed.
Post#8
"The PAL12 is 100db (99.7204) @ 40hz and my opinion wipes the floor with the THAM12 and worth every inch of the additional size"
Origin of the above comment here
Size
15"W 38"H 30"D
Plan here
https://www.diyaudio.com/community/attachments/pal12_2d_2013_apr14-pdf.342680/
PRV 12SW1600 sim
Original thread here
See post#1
Called the PAL12
It was designed for he LAB12 driver
But sim well with other 12's
I can recommend you some 12's that I have simmed.
Post#8
"The PAL12 is 100db (99.7204) @ 40hz and my opinion wipes the floor with the THAM12 and worth every inch of the additional size"
Origin of the above comment here
Size
15"W 38"H 30"D
Plan here
https://www.diyaudio.com/community/attachments/pal12_2d_2013_apr14-pdf.342680/
PRV 12SW1600 sim
post#40 have the HR screen
https://www.diyaudio.com/community/...d-pa-tapped-horn-35hz-extension.232219/page-2
mine is the same... except for some thiele small LAB12 discrepancies , i copied mine from the eminence page
but they are a little different from the original post
more below I simmed the PRV 12W1600, it have 4" Voice Coil and 22.5 BL
Hey bogger
so does the PRV looks ok for the PAL12 ?
PRV 12W1600
https://www.diyaudio.com/community/...d-pa-tapped-horn-35hz-extension.232219/page-2
mine is the same... except for some thiele small LAB12 discrepancies , i copied mine from the eminence page
but they are a little different from the original post
more below I simmed the PRV 12W1600, it have 4" Voice Coil and 22.5 BL
Hey bogger
so does the PRV looks ok for the PAL12 ?
PRV 12W1600
Original thread here
See post#1
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@Rik_bS and others are kinda convincing me to go with bass reflex...
Do you know any good resources for figuring out the details of the design (modelling, determining if I need any bracing, port size etc.); googling "bass reflex box design" and "how to design bass reflex" did not give me useful results.
Otherwise a question about which direction the speaker should face! I've debated having it face straight down at the ground (with the trailer bottom open about 3" off the ground) - which I hope would distribute the sound equally in all directions... And allow me to have a shape that is low to the ground for center of gravity purposes. (My ideal shape for the speaker would be 28"x22"x10" for a 3.5 ft volume... if having it that narrow would work. But regardless be as low as possible; for example 22x22x12.5 if 10" is too small))
Or would that be terrible and I would want to the speaker to be facing front/back/side (and thus need the height to be at least...16"? if a 15" driver).
Would this all be information I could play with in a simulation software? And if so, what software would you recommend?
Do you know any good resources for figuring out the details of the design (modelling, determining if I need any bracing, port size etc.); googling "bass reflex box design" and "how to design bass reflex" did not give me useful results.
Otherwise a question about which direction the speaker should face! I've debated having it face straight down at the ground (with the trailer bottom open about 3" off the ground) - which I hope would distribute the sound equally in all directions... And allow me to have a shape that is low to the ground for center of gravity purposes. (My ideal shape for the speaker would be 28"x22"x10" for a 3.5 ft volume... if having it that narrow would work. But regardless be as low as possible; for example 22x22x12.5 if 10" is too small))
Or would that be terrible and I would want to the speaker to be facing front/back/side (and thus need the height to be at least...16"? if a 15" driver).
Would this all be information I could play with in a simulation software? And if so, what software would you recommend?
If you go BR, don't use the NDL76, it's not suited for that due to the low Q without extensive eq. The Kappalites have a hgher qts and so model better in a reflex. THe Kappalite 3015LF is a very good one for this, in less than 3cuft you can easely reach 50H F3, and it's higher efficient.
If you make a TH, it can be otherwise (i'm not a specialist in those), but for reflex the B&C is very unfit.
If you make a TH, it can be otherwise (i'm not a specialist in those), but for reflex the B&C is very unfit.
If you want to limit the volume of the cabinet to only 3.5 cubic feet, BR is a good choice.
If you can accept ~doubling the volume using a TH like the SS15, for a similar SPL you can use about 1/4 the amplifier and battery power due to it's +6dB sensitivity increase.
Saving over half the battery cost is a big deal, though on average your electric motor will probably draw considerably more than the sub.
Construction details like bracing depend on cabinet size and shape.
Makes no difference for frequencies below ~100 Hz.
Either of those dimensions are OK, low frequency output is dependent on cabinet volume and Fb (box tuning).
Hornresp is good for modeling all types of sub enclosure designs.
WinISD is simpler to use. Both programs are free.
For a BR the driver need to be front of the public, port can be anywhere as long as it's not to far of the driver (or the cabinet start to act as a MLTL with different rules and higher tuning for the same size). So your cabinet need to be at least higher than the driver itself. If you cross it low enough to the midbass driver (not higher than 100Hz) then you can point the driver to the floor if there is at least some space there. Like that you use also the road as load (if the space is narrow) or as reflector for your bass, what will make it louder. But you need at least a few inches clearance for that. And flueds and dust from the road may damage your driver soon (so not so durable).
My updated plan:
Build a BR with the HO 15" version of https://www.parts-express.com/Eminence-KAPPALITE-3015LF-Neo-15-Driver-290-598?quantity=1
The box would be 28*23*18" for a volume of 6.7 cu ft. This would be 18" "high" with the driver and ports on the 28x23 side facing downwards, about 8" off the ground.
Tuning the port for 40 hz requires 4 4" ports which is... expensive. (or 2 6"). So rather than spending $100 on ports, I'm thinking of building it out of wood - having a 23x3" hole in the front, with a 9" long piece of wood inside, making a long rectangular port.
This means the port would be occupying 0.3 cu ft in the box; so I should increase the 'height' of the box by an inch, which will compensate and keep the size at 6.7.
WinISD graphs below.
I would build this ideally out of 1/2 ply... how should I figure out how much bracing to do and where?
How does this plan sound? What changes would you recommend?
Build a BR with the HO 15" version of https://www.parts-express.com/Eminence-KAPPALITE-3015LF-Neo-15-Driver-290-598?quantity=1
The box would be 28*23*18" for a volume of 6.7 cu ft. This would be 18" "high" with the driver and ports on the 28x23 side facing downwards, about 8" off the ground.
Tuning the port for 40 hz requires 4 4" ports which is... expensive. (or 2 6"). So rather than spending $100 on ports, I'm thinking of building it out of wood - having a 23x3" hole in the front, with a 9" long piece of wood inside, making a long rectangular port.
This means the port would be occupying 0.3 cu ft in the box; so I should increase the 'height' of the box by an inch, which will compensate and keep the size at 6.7.
WinISD graphs below.
I would build this ideally out of 1/2 ply... how should I figure out how much bracing to do and where?
How does this plan sound? What changes would you recommend?
Simulating it in Hornresp showed similar results, but with a more realistic high frequency behavior.
And my bracing plan below
And my bracing plan below
Thanks @BP1Fanatic ! I'm guessing you are recommending building that? What kind of horn would that be called? transmission line?
What are the benefits of that horn? It seems to have about the same power as the one I designed with a narrower less stable workable band.
I modeled it in F360 and it does seem to be a bit smaller and use less material. And it would be firing facing front/back/side rather than straight down.
Compared to the parts from my design, when overlayed on an 4'x8' sheet. With mine much of the extra wood is due to bracing. What kind/how much bracing would your design need?
What are the benefits of that horn? It seems to have about the same power as the one I designed with a narrower less stable workable band.
I modeled it in F360 and it does seem to be a bit smaller and use less material. And it would be firing facing front/back/side rather than straight down.
Compared to the parts from my design, when overlayed on an 4'x8' sheet. With mine much of the extra wood is due to bracing. What kind/how much bracing would your design need?
Using a bass tube with 2 inch pvc pipe to lengthen the port would be a whole lot lighter to tow. Adjusting the port length to the desired sound . A pair of ported 6×9 speakers may work really well
@stocktrader200 what do you mean by 6x9 speaker?
Otherwise when I looked at traditional ports even with 2 4" ports the port air velocity was far too high. I had to have 4 4" ports or 2 6" ports to have a reasonable port air velocity
Otherwise when I looked at traditional ports even with 2 4" ports the port air velocity was far too high. I had to have 4 4" ports or 2 6" ports to have a reasonable port air velocity
Yes. It's a tapped quarter wave pipe or tube (straight flare tapped horn with a compression chamber).
Your 1st pic is missing the panel behind the speaker panel.
Higher efficiency, lower distortion, and built-in speaker protection are the benefits.
Also, my design is smaller than your design with better output in the frequency range you prescribed.
Also, you can move the mouth to side exit or at the bottom. You will have to make the front panel the full height of the enclosure and shorten the bottom panel by 6".
This comment made me go back to the tape measure to visualize... and I realized my design while perfect for the trailer would not fit in my storage area in my apartment... and your design is better but still... a little too big.
So i'm back to the initial plan of building a tham12 (14x20x22inches)- just bought a 18awg nailer for it.
That will go up to about 150hz (see graph)... though with good DSP programming (which i hope to do) would I be able to push it to 200?
On that note, I've started looking into what speakers to pair it with (one of my existing hifi speakers I was using on it has gone bust... probably a few drops too many).
I'm only feeding the sub about 300W, and I have about 200W for each speaker (I'm running https://www.parts-express.com/Sure-...dio-Amplifier-Board-T-Amp-320-3351?quantity=1).
So I was wondering if a box with 2 of https://www.parts-express.com/GRS-6PT-8-6-1-2-Paper-Cone-Prosound-Woofer-8-Ohm-292-800?quantity=1 in parallel in a 0.86ft3 (8x16x12in) box in addition to https://www.parts -express.com/CES201-Speaker-299-4180 this horn tweeter.
(With ultimate goal of 2 boxes; one for each channel).
I'm unsure how power for tweeters I should plan for. Would something like https://www.parts-express.com/PRV-A...ullet-Super-Tweeter-8-Ohm-294-2809?quantity=1 be better?
Also for the DSP'ing (I have https://www.parts-express.com/Dayto...-DSP-Expansion-2-In-3-Out-325-1300?quantity=1) should I get a microphone? Is there anything cheaper than https://www.minidsp.com/products/acoustic-measurement/umik-1 ? Would something like https://www.parts-express.com/Dayto...SB-C-Calibrated-Microphone-390-813?quantity=1 work?
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My suggest
ion, based on what I've read so far ...
Don't do THs or similar. They're bigger and heaver than BRs, and have a limited bandwidth. MLTLs and BRs are a better fit IMO for your needs: you can run them up to higher frequencies, which have a direct impact on what you need to settle on to fill in the rest of the spectrum. A good example of what I'm talking about happened this weekend - my miniPA system consists of basically my POC3 TH and two 8x1 tops. However, my youngest daughter is using that for house music for the next few days, so I had to come up with a replacement. The replacement is my POC7 MLTL and two Monoprice outdoor speakers with customized crossovers, high-passed at 150 Hz. The POC7 MLTL can be run up to 200 Hz, so there was no gap in the midbass region, and the whole package fit in, and was used from, the trunk of my car (I'm trying to figure out a way to put the two Monoprice speakers on stands). There is no way that arrangement would have worked if the bass was being provided from a TH with its limited usable upper bandwidth.
I would suggest going with sonotube enclosures for the bass speakers (so obviously a BR solution). Check the lowest impedance you can connect to the channel of the amp you're using and ensure that your subwoofer design matches that impedance, otherwise you're sacrificing output. For example, the lightest solution might be 4 sonotube BRs using the Eminence Kappalite 3012LF to present a 2 ohm load to the amp, but that might be a bit expensive. You could replace the Kappalites with Dayton Audio 12LF400s, which will increase the weight, but will be a lot less expensive overall. If you've got DSP, you can design with adjustable ports in mind. Longer ports for more output at low frequencies, shorter ports for higher output, use DSP to get rid of any in-band peaks or dips.
ion, based on what I've read so far ...
Don't do THs or similar. They're bigger and heaver than BRs, and have a limited bandwidth. MLTLs and BRs are a better fit IMO for your needs: you can run them up to higher frequencies, which have a direct impact on what you need to settle on to fill in the rest of the spectrum. A good example of what I'm talking about happened this weekend - my miniPA system consists of basically my POC3 TH and two 8x1 tops. However, my youngest daughter is using that for house music for the next few days, so I had to come up with a replacement. The replacement is my POC7 MLTL and two Monoprice outdoor speakers with customized crossovers, high-passed at 150 Hz. The POC7 MLTL can be run up to 200 Hz, so there was no gap in the midbass region, and the whole package fit in, and was used from, the trunk of my car (I'm trying to figure out a way to put the two Monoprice speakers on stands). There is no way that arrangement would have worked if the bass was being provided from a TH with its limited usable upper bandwidth.
I would suggest going with sonotube enclosures for the bass speakers (so obviously a BR solution). Check the lowest impedance you can connect to the channel of the amp you're using and ensure that your subwoofer design matches that impedance, otherwise you're sacrificing output. For example, the lightest solution might be 4 sonotube BRs using the Eminence Kappalite 3012LF to present a 2 ohm load to the amp, but that might be a bit expensive. You could replace the Kappalites with Dayton Audio 12LF400s, which will increase the weight, but will be a lot less expensive overall. If you've got DSP, you can design with adjustable ports in mind. Longer ports for more output at low frequencies, shorter ports for higher output, use DSP to get rid of any in-band peaks or dips.
I'm not a fan of the sonotube idea since I don't think those will store very efficiently. But looking at a 3.4ft box (same as tham12) with 2 of the dayton speaker you mentioned... has a similar frequency response as the tham12 but with 10 db less sound. If I mass correctly that is the equivalent of sending an order of magnitude more power into the speaker in order to get the same loudness. And high passing at 150hz would fit what the tham12 seems to do https://www.martinsson.cc/blog/images/THAM12_FINAL_HRSPL1PI_BC_12NDL76.jpg .
I've not found a good primer on MLTLs; please share if you know of any because i don't know enough to compare or design one.
(Though this box, since it's meant to be played in open ground in the middle of a crowd, i could make it 21*23*12 with one speaker on either side and the ports on the front/back... though would that make it an isobaric design?
I've not found a good primer on MLTLs; please share if you know of any because i don't know enough to compare or design one.
(Though this box, since it's meant to be played in open ground in the middle of a crowd, i could make it 21*23*12 with one speaker on either side and the ports on the front/back... though would that make it an isobaric design?
Comparing bass reflex with 2 of the dayton speaker, vs 1 of the eminence speaker (2 is better but out of budget)... The dayton audio speaker (with 2 of them) is... 30 pounds heavier... which is a lot. (Both modelled in a 3.4cu ft box at 300w) with tuning adjusted to what seems like the lowest f3 point to me.
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